Had an issue today where GMail was duplicating e-mails in the sent folder of Outlook and GMail.  
Resolution:  Check Box, Do Not Save Copies of Sent Items. in Outlook.


Found a great article on duplication of e-mails with Outlook and G Suite today at http://www.pstrepairtool.org/blog/prevent-duplicate-sent-items-gmail-outlook.html.  We were able to solve the issue with the top information.  Outlook seems to be saving the e-mail in the sent folder, then syncing the duplicate to GMail through IMAP or G-Suite Sync.  


In Microsoft Outlook 2016 and 2013 Versions

To turn off this option in MS Outlook 2013 and 2016, follow the below mentioned steps:

1. Open "Microsoft Outlook" >> Click on "File" tab >> "Info" >> "Account Settings" >> "Account Settings"

2. Select Gmail account >> Click on "Change…" >> Click on "More Settings…" >> Go to "Advanced" tab.

3. Go to "Sent Items" section >> Check "Do Not Save Copies of Sent Items" options.


For Microsoft Outlook 2010

To turn off this option in MS Outlook 2010 version, follow the below steps:

1.  Open "Microsoft Outlook" >> Click on "File" tab >> "Info" >> "Account Settings" >> "Account Settings…"

2.  Select Gmail account >> Click on "Change…" >> Click on "More Settings…" >> Go to "Advanced" tab.

3.  Click on "Sent Items" tab >> enable "Do not save copies of sent items" option.


For Microsoft Outlook 2007

To turn off this option in MS Outlook 2007 version, follow the below steps:

1.  Open Microsoft Outlook 2007 >> Go to "Tools" >> "Account Settings…"

2.  Select your Gmail account >> Click on "Change…" button >> Click on "More Settings…" >> Click on "Folders" tab

3.  Enable the option "Save sent mail in the Outlook Sent Items folder".



hit account settings in Outlook 2016


select gmail account


Check the Option


For Microsoft Outlook 2010

To turn off this option in MS Outlook 2010 version, follow the below steps:

1.  Open "Microsoft Outlook" >> Click on "File" tab >> "Info" >> "Account Settings" >> "Account Settings…"

2.  Select Gmail account >> Click on "Change…" >> Click on "More Settings…" >> Go to "Advanced" tab.

3.  Click on "Sent Items" tab >> enable "Do not save copies of sent items" option.


click account settings in Outlook 2010


Choose Gmail account


Check the option

For Microsoft Outlook 2007

To turn off this option in MS Outlook 2007 version, follow the below steps:

  • Open Microsoft Outlook 2007 >> Go to "Tools" >> "Account Settings…"
  • Select your Gmail account >> Click on "Change…" button >> Click on "More Settings…" >> Click on "Folders" tab
  • Enable the option "Save sent mail in the Outlook Sent Items folder".


Select option